with the cars all being the hydrolic cam, one would have to assume the cam was indeed a different grind. i will never argue the poly would make 260hp, but from my experience, just bolting a 4bbl to a truck motor does not get you 60hp. a good hydrolic grind cam, some mild clean up on the heads, headders, elect ign, and a 4bbl would push you well beyond the 300hp mark pretty easy. its a great motor, but in stock truck form, id stick with a good carter 2bbl unless your planing on doing some upgrades to the motor to go with the 4bbl.

just one guys opinion formed after hundreds of thousands of miles driving poly powered pickups